1. Field of the Invention
This invention relates to telecommunications and data systems, and, more particularly, to providing telephony and data network traffic over a single communications channel, such as a single two-wire telephone line.
2. Description of the Relevant Art
As newer telecommunications services have become more prevalent, existing buildings such as hotels, apartments and office buildings desire to offer these services to their inhabitants, e.g., hotel guests, apartment dwellers or office workers. However, existing buildings such as hotels and apartments have generally been unable to offer these newer telecommunication services due to the high cost of adding additional communications lines. The present cost of retrofitting existing buildings is $400 per room or more in many cases.
For example, the majority of hotels are wired such that only a single copper pair is provided to each room for a single telephone line. However, this is inadequate for standard services such as Ethernet, or simply providing two or more telephone lines to a room.
Even some recently built apartment complexes find that the wiring for their telecommunications services is underground with buried runs of several hundred feet, too far to provide Ethernet service. For example, consider an apartment complex comprising twenty small building with four to eight units per building. All wires for the telephones come to one collection point and then travel underground for about 300-m (1000-ft) to the clubhouse building. The 300-m run is in excess of the 100-m limit for Ethernet. The complex is pre-wired for telephones and cable but not high speed Internet access.
Additionally, many apartment complexes are now in the business of reselling primary telephone services using an in-house PBX. Many times, the apartment complex overcommits its telephony resources by leasing a small number of telephone lines for the PBX and providing telephone service to a larger number of apartments at a price slightly less than direct service would cost. As xDSL does not cross a PBX, being a direct connection from the central office to the end-user, the apartment complex is unable to provide xDSL to each apartment using the same method used to provide telephone service.
FIG. 1xe2x80x94PBX Telephony System 100
FIG. 1 illustrates a basic analog two-wire telephone connection setup 100 in the prior art. The public switched telephone network (PSTN) lines 105 are provided from the central office to a main wiring distribution facility 110 in the general vicinity of an end-user. As illustrated, the end-user is shown at a location 130A. Generally speaking, the illustrated embodiment is that of an office, hotel, or apartment complex, where the locations 130 comprises offices, hotel rooms, or apartments. Each location 130 receives telephone services through a local PBX 112.
As shown, FIG. 1 includes a main wiring distribution facility 110 including a PBX 112 coupled to receive digital telephony signals from the public switched telephone network (PSTN) 105. Line 120, shown here becoming line 120, coupled the main wiring distribution facility 110 to a first one of a plurality of user locations, including user location 130A. User location 130A, as shown, includes a junction box 132, e.g. a station jack 132, coupled to line 120. Station jack 132 couples to a first telephone 134A and a second telephone 134B. A modem jack 136 splits off of the wiring of station jack 132 to a data processing unit 138, e.g. computer 138.
Telephone signals from the PSTN 105 are routed from the PBX 112 as separate communications channels 120. Each communications channel 120 comprises one telephone line, usually with dial tone and frequently with additional telephony services such as last number redial, call waiting, etc. The individual telephone lines 120 are typically cross-connected through so-called 66 boards (or 110 boards) to a two-wire telephone line 120. The two-wire telephone line 120 runs from the main wiring distribution facility 110 to the end-user site 130A. The two-wire telephone line 120 typically comprises two copper wires that meet the requirements of Category 3 of the ANSI/TIA/EIA-568-A Standard entitled xe2x80x9cCommercial Building Telecommunications Cabling Standardxe2x80x9d, and are often referred to as xe2x80x9cCat 3xe2x80x9d wires.
At the end-user site 130A, the two-wire telephone line 120 terminates at a telephone outlet 132, including a junction box (usually a J box) and a telephone jack (usually an RJ-11 socket). Typically, an RJ-11 socket in the J box 132 receives an RJ-11 plug that connects a line to the end-user telephone 134. A modem 136 is often also connected into the same line, either through an extension outlet in a duplicate J box, or by unplugging the telephone 134 and plugging in the modem 136. The modem 136 provides data communications to a computer 138 over the telephone line 120. It is noted that while newer telephony installations may include four-wire telephone lines (so called cat5 defined by the ANSI/TIA/EIA-568-A Standard referenced above), many existing telephone lines are still two-wire telephone lines 120 (cat3).
In a general way, the prior art system of FIG. 1 operates as follows. Power for the communications over the communications channel are provided over the two-wire telephone lines 120 over which the communications are transmitted. To announce an incoming communication (i.e. a telephone call) coming in over the PSTN 105, a ring voltage (such as 48 V DC) is sent from the central office to the PBX 112. The PBX 112 sends ring voltage through the 66 box 114A, over the two-wire telephone line 120, through the RJ-11 socket in the J box 132, and into the telephone 134, which then rings. A ring may be mechanically or electronically generated. When the end-user answers the telephone call, the telephone 134 goes off-hook, and a full duplex communications stream of up to 64 kbps may be transmitted over the two-wire telephone line 120 back to the switching location 110, through the PBX 112, to the calling party.
Data communications between the computer 136 and an external network are over the same two-wire telephone line 120 as voice telephone communications. In general, data and voice are not multiplexed over the two-wire telephone line 120, although this may be performed, usually through the computer 136. The modem typically transfers data using the V.90 protocol, although other protocols (V.34, etc.) are also used. Data transfer rates are generally limited to 56 kbs downstream to the computer 136 and 53 kbps upstream.
Recent developments have led to some merging of multiple communications lines onto fewer numbers of communications channels. For example, ISDN (Integrated Services Digital Network) communications provides for simultaneous voice and data connections over the existing telephone infrastructure.
Digital Subscriber Line (DSL) provides for POTS telephony communications in the lower frequency band coupled with digital communications in the upper frequency bands. In Digital Subscriber Line communications (generally designated as xDSL), the communications channel is pinged to characterize the channel, typically a four-wire telephone line. The frequency spectrum of the channel is then divided into sub-channels or bins for data transmission. The number and division of the sub-channels may be determined by the channel response, up to the limits of the particular communications scheme chosen. The maximum data throughput on xDSL ranges from 128 kbps duplex using IDSL (ISDN DSL) to 52 Mbps downstream and 1.5 Mbps upstream using VDSL (Very high bit rate DSL). It is noted that SDSL (Symmetric DSL), also called HDSL (High bit rate DSL), uses a two-wire telephone line to deliver up to 2.0 Mbps duplex.
As another example, U.S. Pat. No. 5,844,596 teaches that two pairs of telephone wires may be used, along with a low pass filter and a high pass filter, to route a telephone line and a video connection to a desired location. This method has the advantage of routing two different communication lines onto a single communications channel consisting of a two-wire telephone line. This disclosure teaches that the voice data is segregated into a sub-channel in the voice frequency band. Video or other data are transmitted over a higher frequency range different and separate from the voice frequency range. The data throughput taught is less than 64 kbps total.
Applicant is aware of several systems from Tut Systems which also purport to provide voice and data connectivity over existing wiring.
FIG. 2xe2x80x94Telephony System 200 with POTS and DSL
FIG. 2 illustrates an example of a prior two-wire telephone line communications channel 220, including one telephone line and data signals. The single telephone line is provided by a POTS line from the PBX 112, while the data signals are provided through DSL transceiver 236A at a main wiring distribution facility 210. The DSL signals from DSL transceiver 236A are added to telephone line 120 in the higher frequency range while the POTS telephone signals are transmitted in the lower frequency range. The POTS line and the DSL signals are provided to the user location 230A, which may be one of a plurality of user locations 230.
As shown, FIG. 2 includes a main wiring distribution facility 210 including a PBX 112 coupled to receive digital telephony signals from the PSTN 105. PBX 112 is coupled to POTS splitter 214 through line 120. DSL transceiver 236A couples network signals from the network 205 to the over line 216 to the POTS splitter 214. The main wiring distribution facility 210 is coupled to the user location 230A by a two-wire telephone line 120. At the user location 230A, a station jack 232 receives POTS telephone signals and the DSL signals, providing the POTS telephone signals to a telephone 134 and the digital DSL signals to a DSL transceiver 236B. The digital transceiver 236B is coupled to a computer 138.
Telephone signals from the PSTN 105 are routed from the PBX 112 as separate communication channels 120. Each communication channel 120 comprises one telephone line, usually with dial tone and frequently with additional telephony services, as mentioned above, over a two-line telephone line 120. The DSL transceiver 236A operates to convert network traffic coming over network 205 into DSL traffic routed over line 216 on to cat 3 telephone line 120 at POTS splitter 214.
At the end-user site 230A, the two-wire telephone line 120 terminates at a station jack 232. Station jack 232 typically includes a junction box (usually a J box) and a telephone jack (usually an RJ-11 socket). Typically, the RJ-11 socket in the J box receives an RJ-11 plug that connects a line to the end-user telephone 134. The second DSL transceiver 236B is coupled to two-wire telephone line 120 at station jack 232. The DSL transceiver 236B is a separate device outside the station jack 232 and couples typically only to the computer 138. The use of DSL transceiver 236B typically replaces the use of a modem in the computer 138.
In a general way, the prior art system 200 of FIG. 2 operates as follows. As with the system of prior art FIG. 1, POTS telecommunications are provided from the PSTN 105, through the PBX 112, over the two-wire telephone line 120, to the station jack 232, to the end-user telephone 134. Data communications between the computer 138 and an external network 205 are over the same two-wire telephone line 120 as the POTS voice telephone communications.
What is needed is a system and method for retrofitting buildings with improved telecommunications services over the existing telephone wiring. Also desirable is a system and devices for providing a plurality of voice telephone sub-channels and a network data sub-channel over a single two-wire telephone line. The total bandwidth would preferably exceed 4 Mbps of throughput and possibly be as high as 100 Mbps.
The present invention provides an improved system and method for retrofitting telecommunications infrastructures of existing buildings with new telecommunications services. The present invention allows new telecommunications services to be provided over existing telephone lines with reduce cost. The present invention also includes an improved system and method for providing a plurality of telephone connections and data traffic over a single communications channel. The present invention also provides improved telephony line interface module and telephony device embodiments which effectively implement line card functionality in the telephony line interface module and/or telephony device, respectively.